include/linux/percpu.h

   1 #ifndef __LINUX_PERCPU_H
   2 #define __LINUX_PERCPU_H
   3
   4 #include <linux/preempt.h>
   5 #include <linux/slab.h> /* For kmalloc() */
   6 #include <linux/smp.h>
   7 #include <linux/cpumask.h>
   8
   9 #include <asm/percpu.h>
  10
  11 #ifdef CONFIG_SMP
  12 #define DEFINE_PER_CPU(type, name)                                      \
  13         __attribute__((__section__(".data.percpu")))                    \
  14         PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
  15
  16 #ifdef MODULE
  17 #define SHARED_ALIGNED_SECTION ".data.percpu"
  18 #else
  19 #define SHARED_ALIGNED_SECTION ".data.percpu.shared_aligned"
  20 #endif
  21
  22 #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)                       \
  23         __attribute__((__section__(SHARED_ALIGNED_SECTION)))            \
  24         PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name             \
  25         ____cacheline_aligned_in_smp
  26 #else
  27 #define DEFINE_PER_CPU(type, name)                                      \
  28         PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
  29
  30 #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)                     \
  31         DEFINE_PER_CPU(type, name)
  32 #endif
  33
  34 #define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
  35 #define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
  36
  37 /* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
  38 #ifndef PERCPU_ENOUGH_ROOM
  39 #ifdef CONFIG_MODULES
  40 #define PERCPU_MODULE_RESERVE   8192
  41 #else
  42 #define PERCPU_MODULE_RESERVE   0
  43 #endif
  44
  45 #define PERCPU_ENOUGH_ROOM                                              \
  46         (__per_cpu_end - __per_cpu_start + PERCPU_MODULE_RESERVE)
  47 #endif  /* PERCPU_ENOUGH_ROOM */
  48
  49 /*
  50  * Must be an lvalue. Since @var must be a simple identifier,
  51  * we force a syntax error here if it isn't.
  52  */
  53 #define get_cpu_var(var) (*({                           \
  54         extern int simple_identifier_##var(void);       \
  55         preempt_disable();                              \
  56         &__get_cpu_var(var); }))
  57 #define put_cpu_var(var) preempt_enable()
  58
  59 #ifdef CONFIG_SMP
  60
  61 struct percpu_data {
  62         void *ptrs[1];
  63 };
  64
  65 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
  66 /*
  67  * Use this to get to a cpu's version of the per-cpu object dynamically
  68  * allocated. Non-atomic access to the current CPU's version should
  69  * probably be combined with get_cpu()/put_cpu().
  70  */
  71 #define percpu_ptr(ptr, cpu)                              \
  72 ({                                                        \
  73         struct percpu_data *__p = __percpu_disguise(ptr); \
  74         (__typeof__(ptr))__p->ptrs[(cpu)];                \
  75 })
  76
  77 extern void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask);
  78 extern void percpu_free(void *__pdata);
  79
  80 #else /* CONFIG_SMP */
  81
  82 #define percpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
  83
  84 static __always_inline void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
  85 {
  86         return kzalloc(size, gfp);
  87 }
  88
  89 static inline void percpu_free(void *__pdata)
  90 {
  91         kfree(__pdata);
  92 }
  93
  94 #endif /* CONFIG_SMP */
  95
  96 #define percpu_alloc_mask(size, gfp, mask) \
  97         __percpu_alloc_mask((size), (gfp), &(mask))
  98
  99 #define percpu_alloc(size, gfp) percpu_alloc_mask((size), (gfp), cpu_online_map)
 100
 101 /* (legacy) interface for use without CPU hotplug handling */
 102
 103 #define __alloc_percpu(size)    percpu_alloc_mask((size), GFP_KERNEL, \
 104                                                   cpu_possible_map)
 105 #define alloc_percpu(type)      (type *)__alloc_percpu(sizeof(type))
 106 #define free_percpu(ptr)        percpu_free((ptr))
 107 #define per_cpu_ptr(ptr, cpu)   percpu_ptr((ptr), (cpu))
 108
 109 #endif /* __LINUX_PERCPU_H */